gh-96538: Fix refleak in _bisectmodule.c (gh-96619)

Lib/test/test_bisect.py

@@ -263,6 +263,34 @@ class TestBisect:
         for f in (self.module.insort_left, self.module.insort_right):
             self.assertRaises(TypeError, f, x, y, key = "b")
 
+    def test_lt_returns_non_bool(self):
+        class A:
+            def __init__(self, val):
+                self.val = val
+            def __lt__(self, other):
+                return "nonempty" if self.val < other.val else ""
+
+        data = [A(i) for i in range(100)]
+        i1 = self.module.bisect_left(data, A(33))
+        i2 = self.module.bisect_right(data, A(33))
+        self.assertEqual(i1, 33)
+        self.assertEqual(i2, 34)
+
+    def test_lt_returns_notimplemented(self):
+        class A:
+            def __init__(self, val):
+                self.val = val
+            def __lt__(self, other):
+                return NotImplemented
+            def __gt__(self, other):
+                return self.val > other.val
+
+        data = [A(i) for i in range(100)]
+        i1 = self.module.bisect_left(data, A(40))
+        i2 = self.module.bisect_right(data, A(40))
+        self.assertEqual(i1, 40)
+        self.assertEqual(i2, 41)
+
 class TestBisectPython(TestBisect, unittest.TestCase):
     module = py_bisect
 

Modules/_bisectmodule.c

@@ -120,6 +120,7 @@ internal_bisect_right(PyObject *list, PyObject *item, Py_ssize_t lo, Py_ssize_t
             }
             else {
                 res = PyObject_IsTrue(res_obj);
+                Py_DECREF(res_obj);
             }
         }
         else {
@@ -299,6 +300,7 @@ internal_bisect_left(PyObject *list, PyObject *item, Py_ssize_t lo, Py_ssize_t h
             }
             else {
                 res = PyObject_IsTrue(res_obj);
+                Py_DECREF(res_obj);
             }
         }
         else {